Catheters are medical devices that are used to deliver or retrieve objects in the body. The catheter tip is inserted into the body through a natural or artificial opening and delivered to a desired location. For example, a catheter is used to deliver and deploy a stent in an arterial stenosis. Endoscopic catheters are used to deliver an imaging device for gastrointestinal use.
U.S. Pat. No. 5,437,638 to Bowman discloses a multilumen catheter having a plurality of inflatable tubes at its tip. Each tube is attached to a different lumen, so that each tube may be individually inflated and deflated. The tubes are initially inserted into their respective lumens. In a procedure to open a constricted body passage, the tubes are inflated in the constriction. The tubes may also be provided with gripping surfaces and are manipulated by appropriate fluid pressures to grasp and recover objects in a body passageway.
U.S. Pat. No. 5,941,895 to Myler et al discloses a catheter for the retrieval of a stent. The catheter includes a tubular body and an axially moveable guidewire that are adapted to grasp engagement members on a stent to be retrieved.
U.S. Pat. No. 5,109,830 to Cho discloses a catheter having a tip designed to facilitate navigation of the catheter through the cardiovascular system. The tip has an inner element having a memorized preformed curved shape that it assumes when it is not disposed within an outer restraining sleeve. When in the sleeve, the inner element is straightened by the rigidity of the sleeve. The inner element is removed from the sleeve in order to facilitate navigation of the tip around a curve or bend in a blood vessel. The inner element is disposed in the sleeve when passing through a straight region of a blood vessel.
U.S. Pat. No. 4,597,389 to Ibrahim discloses a catheter having an annular balloon at its tip for grasping an object. The catheter tip is delivered to the object to be grasped with the balloon in its deflated state. The balloon is then positioned with the object in the central passageway of the annular balloon. As the balloon is inflated, the central passageway becomes constricted so as to grasp the object. The catheter is then withdrawn from the body.